Study On Wind Load Characteristics And Peak Responses Of Long-span Roof Structures Considering Wind Direction Changes

At present,the consideration of wind load in structural wind resistance design generally does not include the influence of wind direction changes,and it is conservatively assumed that the wind acts on the structure from the main wind direction of the city or the most unfavorable direction of the structure.The wind load characteristics and peak response of the structure are different in different directions.The wind resistance design from the main wind direction of the city or the most unfavorable wind direction of the structure is bound to affect the safety and comfort of the structure.Therefore,it is necessary to study the wind load characteristics and peak response of long-span roof structures under wind direction changes.This thesis conducts experimental research with Qingdao Railway Station as the background,and compares and analyzes the wind load characteristics and peak response considering wind direction changes and traditional analysis methods.The conclusions are as follows:(1)The wind load characteristics of the long-span roof structure with the change of wind direction and the fixed wind downward are compared and analyzed,and the wind load characteristics on the surface of the long-span roof structure are mainly affected by the wind direction and the position of the wind load.(2)The average value of the displacement response of each measuring point of the long-span roof structure under the most unfavorable wind direction angle is larger than the average value of the displacement response considering the wind direction change,but smaller than its pulsation value.(3)The wind vibration response time history of each typical measurement point of the long-span roof structure under the traditional analysis method conforms to the Gaussian distribution and belongs to a stationary signal,while the wind vibration response time history under the change of wind direction is basically a non-stationary random signal,and some of these wind-induced response time histories belong to Gaussian distribution,and some belong to non-Gaussian distribution.(4)The wind vibration response time history of the long-span roof structure obtained by considering the change of wind direction and the wind vibration response time history of the long-span roof structure obtained without considering the change of the wind direction are compared and analyzed,it shows that the peak factor of the response time history belonging to the Gaussian region is between 2.5 and 4,the peak factor of the response time history belonging to the non-Gaussian region is larger than the peak factor of the response time history belonging to the Gaussian region.In addition,the skewness and kurtosis of the wind-induced response time history of some measurement points that belong to the non-Gaussian region are very large.Analyzing the calculated peak response,it shows that when considering the change of wind direction,the peak response at the measuring point in the center of the roof is smaller than the peak response obtained by the traditional analysis method,the peak response of the remaining measuring points is at least 6.4% larger than the peak response obtained under the most unfavorable wind direction angle.This shows that the wind-resistant design of long-span roof structures with traditional analysis methods is conservative for some nodes and dangerous for some nodes.It is more reasonable to carry out the wind-resistant design of the long-span roof structure when considering the change of wind direction.